Nakagawa Kento, Kawashima Saeko, Fukuda Kazuki, Mizuguchi Nobuaki, Muraoka Tetsuro, Kanosue Kazuyuki
Faculty of Sport Sciences, Waseda University, Saitama, Japan.
Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan.
Front Hum Neurosci. 2023 Jun 30;17:1133279. doi: 10.3389/fnhum.2023.1133279. eCollection 2023.
Interlimb coordination involving cyclical movements of hand and foot in the sagittal plane is more difficult when the limbs move in opposite directions compared with the same direction (directional constraint). Here we first investigated whether the directional constraint on hand-foot coordination exists in motor imagery (imagined motion). Participants performed 10 cyclic coordinated movements of right wrist flexion-extension and right ankle dorsiflexion-plantarflexion as quickly and precisely as possible, in the following three conditions; (1) actual movements of the two limbs, (2) imaginary movements of the two limbs, and (3) actual movement of one limb combined with imaginary movement of the other limb. Each condition was performed under two directions; the same and the opposite direction. Task execution duration was measured as the time between the first and second press of a button by the participants. The opposite directional movement took a significantly longer time than did the same directional movement, irrespective of the condition type. This suggests that directional constraint of hand-foot coordination occurs even in motor imagery without actual motor commands or kinesthetic signals. We secondarily examined whether the corticospinal excitability of wrist muscles is modulated in synchronization with an imaginary foot movement to estimate the neural basis of directional constraint on imaginary hand-foot coordination. The corticospinal excitability of the forearm extensor in resting position increased during dorsiflexion and decreased during plantarflexion similarly in both actual and imaginary foot movements. This corticospinal modulation depending on imaginary movement phase likely produces the directional constraint on the imaginary hand-foot coordination.
与同向运动相比，当手部和足部在矢状面进行周期性运动的双侧肢体以相反方向运动时，双侧肢体协调更加困难（方向限制）。在此，我们首先研究了在运动想象（想象运动）中是否存在对手足协调的方向限制。参与者在以下三种条件下，尽可能快速且精确地进行10次右手腕屈伸和右踝关节背屈-跖屈的周期性协调运动：（1）双侧肢体的实际运动；（2）双侧肢体的想象运动；（3）一侧肢体的实际运动与另一侧肢体的想象运动相结合。每种条件都在两个方向下进行：同向和反向。任务执行持续时间以参与者第一次和第二次按下按钮之间的时间来衡量。无论条件类型如何，反向运动比同向运动花费的时间明显更长。这表明即使在没有实际运动指令或动觉信号的运动想象中，也会出现手足协调的方向限制。其次，我们研究了腕部肌肉的皮质脊髓兴奋性是否与想象中的足部运动同步调制，以估计想象中手足协调方向限制的神经基础。在实际和想象的足部运动中，休息位时前臂伸肌的皮质脊髓兴奋性在背屈时增加，在跖屈时降低。这种取决于想象运动阶段的皮质脊髓调制可能会对想象中的手足协调产生方向限制。
